The invention relates to transfer devices for the administration of materials, as for example for sperm in artificial insemination consisting of a hollow cylindrical catheter open at both ends into which a tubular cartridge of material to be administered may be inserted at the distal or proximal end and a plunger may be inserted from the proximal end to force out the cartridge contents, and a replaceable tubular sleeve adapted to be slid onto the catheter, which has its proximal end detachably secured to the proximal end of the catheter, has a port for the emergence of the material to be administered and is tapered at its distal end and the latter and is provided with a radially symmetrical shaped member having a longitudinal passage therein. Such transfer devices are more especially but not exclusively used for veterinary purposes for artifical insemination or embryo transfer. The first step is for the throw-away sleeve, which is usually made of plastic and tapers conically towards its distal tip conically, to be put on, whereafter the cartridge with the material to be administered is then inserted into the catheter from the proximal end and then, after introduction of the transfer device into the vagina of a cow, for instance, the material is expelled by the plunger. The cartridge may also be inserted from the front prior to putting on the sleeve. The transfer device is suitable for medicaments in a liquid or paste form.
In addition to ampules plastic tubes sealed at both ends are available in various sizes and which have at least two standard diameters. Accordingly thicker or thinner catheters and conical tips having a larger or smaller end opening are required. Sleeves with large and small diameters are conventional.
The attachment of such throw-away sleeves frequently give rise to difficulties.
For the attachment at the distal end a proposal has been made for a design of the initially mentioned type in FIG. 3 of the German unexamined specification 3,106,306, in which case the shaped member is bonded at the front into sleeve and is drawn with the latter onto the catheter. During use there is then the danger of the piston, which strikes the inner cone of the shaped member so as to press forwards and press out the contents of the cartridge, being broken off and being lost in the organ into which the transfer is being made. Such pistons are frequently in the form of small balls--as sealing balls of the cartridge or in the case of a plunger with a spherical tip--of for instance 3 mm in diameter, which are inserted forwards into the cartridge and extrude the contents thereof. When the ball in the end strikes the oblique conical surface it will exert its thrust thereon.
There has been a proposal (see the German patent 2,729,428) to attach the sleeve at the proximal end of the catheter by having a conically flared part of the catheter at this end so that the proximal sleeve end, which is slit for 3 to 4 cm for this purpose, may be slipped onto this end, at which position the sleeve may be clamped in place on the cone with the aid of a retainer ring drawn over it. In accordance with another design in this patent there is stepped helical rib at the proximal end of the catheter onto which the sleeve is screwed. In this case the sleeve may be plain and not slit at the proximal end.
The large number of different cartridges, more especially sperm cartridges and the different diameters of catheter make it necessary for the veterinary surgeon to have a stock of different transfer devices or even only different sleeves, which are drawn over the catheter as a casing. It may well happen that he has the unfortunate experience of seeing that he has the wrong type of sleeve or the wrong transfer device with him. This is more especially likely if it he has to use different cartridges, as is frequently the case with sperm.